High voltage pulser



April 26, 1966 w. P. DYKE HIGH VOLTAGE Filed April 18', 1961 ETAL FULSER3 Sheets$heet l IN V EN TOR S.

Wa/fer P. Dyke BY Frank J. Grundhouser Norman W Sfunkard Buckhorn,Cheafham 8 Blore ATTORNEYS April 26, 1966 w P. DYKE ETAL 3,

HIGH VOLTAGE PULSER Filed April 18, 1961 3 Sheets-Sheet 2 52 32 asmwiINVENTORS.

Walter P Dyke By Frank J. Grundhauser Norman W Sfunkard Buckhorn,Cheat/mm 8 B ore ATTORNEYS April 26, 1966 w. P. DYKE ETAL HIGH VOLTAGEPULSER 3 Sheets-Sheet 5 Filed April 18, 1961 IN VEN TOR 5. Walter P.Dyke Frank J. Grundhauser Norman W. Sfunkard Buckhorn, Cheafham 8 BloreATTORNEYS United States Patent 3,248,574 HIGH VOLTAGE PULSER Walter P.Dyke, McMinnville, and Frank J. Grundhauser and Norman W. Stunkard, LakeGrove, 0reg., assignors to Field Emission Corporation, McMinnville,0reg.,

a corporation of Oregon Filed Apr. 18, 1961, Ser. No. 103,796 7 Claims.(Cl. 307110) This invention relates to a high voltage pulser and moreparticularly to a compact device which will store a substantial amountof electrical energy at a high voltage and which upon being triggeredwill release such energy in the form of a high voltage, high currentnarrow pulse having a short rise time.

The pulser of the present invention was developed to produce pulses ofthe type described above for delivery to specially constructed X-raytubes which can utilize such pulses for producing intense X-rays for avery short period of time, thus enabling X-ray pictures to be secured ofelements such as moving projectiles or events such as explosionsinvolving extremely rapid motion even though the element or event is inthe interior of or behind thick members of metal or other materials. Asa specific example, pulsers in accordance with the present inventionhave been constructed to deliver square wave pulses of electric energyat voltages up to 600 kv. with currents up to 2000 amperes and withpulse lengths as short as 0.03 microsecond and rise times as short as0005 microsecond measured between 10% and 80% of the leading edge of thepulse and with very little overshoot at the beginning of the pulse orundershoot at the end of the pulse. Such pulses when utilize-d in anX-ray tube are effective to stop motion at velocities of 20,000 feet persecond through three inches of aluminum or the equivalent at a distanceof four feet from the tube.

The pulser of the present invention includes a plurality of similarenergy storage modules each of which contains a length of transmissionline which is open at one end and has its other end connected tocharging and discharging circuits. Each transmission line is preferablymade up of a plurality of artificial 'or lumped constant transmissionline sections each including a series inductor and a shunt capacitor,since a greater amount of electrical energy can be stored in a givenspace than when natural or distributed constant transmission lines areemployed although such natural lines in the form of coiled coaxialcables can be employed when very narrow and accurately formed squarewave pulses are desired.

The modules of the present invention. are preferably plug in units whichcan be mounted upon an elongated support by plug in connectors so as tohave one end of .the transmission line connected to spark gap memberscarried by the support. The spark gap members are arranged on thesupport to provide a series of spark gaps which, when broken down,connect such one ends of the transmission lines of the modules in aseries onput circuit but which normally provide gaps in such seriescircuit to enable charging ofthe transmission lines in parallel from ahigh voltage D.C. source. The support also carries a plurality ofinductors connected in a pair of series circuits with individualinductors connected between the spark gap elements of different sparkgaps in order to provide a parallel charging circuit for thetransmission lines while isolating such lines from each .other withrespect to rapidly changing currents.

In a preferred construction the support is an elongated hollow member ofinsulating material closed at its ends. The spark gap members arearranged in two parallel rows along opposite sides of the support andproject inwardly through the walls of the support. Pairs of such membersmade up of a member in each row are in alignment with 3,248,574 PatentedApr. 26, 1966 each other and have their inner ends adjacent each otherto provide the spark gaps referred to above. The inductors which isolatethe various transmission lines of the modules are enveloped in theinsulating material of the support and extend in parallel rowslongitudinally thereof between the rows of spark gap members. Electricalconnections between the ends of the inductors and the spark gap membersare also buried in the insulating material of the support.

The modules include elongated support members between which rigidcapacitor elements extend. Such capacitor elements are rigidly securedto the support elements and the inductors of the transmission line arewound on one of the support elements. One end of each of such supportelements terminates in a plug element which plugs into an exposed end ofa spark gap element to mount the module on the support and makeelectrical connections between one end of the transmission line of themodule to adjacent spark gap members in a row of such members. There isthus a row of such modules attached to the outer surface of the supporton opposite sides of the support. The modules in the two rows are oifsetlongitudinally of the support from each other so that the transmissionlines of the modules and the spark gaps form a series circuit. An outputspark gap between one of the spark gap members referred to above and anauxiliary spark gap member carried by the closure for one end of thesupport is also provided at such end of the support is also included insuch series circuit.

A cover is provided for each of the modules and is re movably secured tothe support in gas tight relationship so that the interior of thesupport forms a closed pressure chamber in which gas under a pressuregreater than ambient atmospheric pressure can be maintained. The sparkgaps referred to above are all in such chamber and form a row of sparkgaps in alignment in a common light path so that each spark gap sees allof the other spark gaps.

When one spark gap breaks down and a spark is produced across such gap,radiation emitted-therefrom causes the gas between all of the otherspark gaps to be ionized so that break down of all of the spark gaps issubstantially instantaneous. Provision is made for applying anadditional triggering voltage across one of such spark gaps when thetransmission lines have been charged to break down such spark gap andcause discharge of all of the transmission lines through an outputcircuit.

, It is therefore an object of the present invention to provide animproved high voltage high current pulser capable of producing narrowand intense square wave pulses of electric energy.

Another object of the invention is to provide a coinpact pulse formingdevice in which a plurality of similar modules including open endedtransmission lines are mounted upon a support and connected to becharged in parallel from a high voltage D.C. source and discharged inseries through an output circuit.

Another object of the invention is to provide a high voltage highcurrent pulser in which a plurality of energy storage modules aremounted-on the outer surface of a hollow support and connected in aseries circuit with spark gaps in the interior of such support andexposed to each other for simultaneous discharge of such modules whencharged to a high voltage and one of such spark gaps is triggered tocause such one gap to break down and emit ionizing radiation from suchone gap to the remaining gaps which causes such gaps to all break downsubstantially instantaneously.

A further object of the invention is to provide a high voltage, highcurrent pulser in which a plurality of detachable energy storage modulesare positioned on the exterior of a hollow elongated support andconnected with discharge spark gaps in the interior of such support andcovers for said modules are secured to said support to provide a gastight pressure chamber for the spark gaps Within such support.

Other objects and advantages of the invention will appear in thefollowing detailed descriptions of specific embodiments shown in theattached drawings of which:

FIG. 1 is a side elevation of a typical pulser in accordance with thepresent invention;

FIG. 2 is a top plan view of the pulser of FIG. 1;

FIG. 3 is a side elevation of the pulser of FIGS. 1 and 2, looking tothe left in such figures with a portion of the vertical length omittedand with parts broken away to show interior structure;

FIG. 4 is a vertical section on an enlarged scale of the pulser of FIGS.1 to 3 on the line 44 of FIG. 3, with a portion of the vertical lengthomitted and certain of the energy storage modules and support portionstherefor shown in elevation and other of the modules shown in verticalsection;

FIG. 5 is a horizontal section of the support of the pulser of FIGS. 1to 4 with the modules omitted and taken approximately on the line 55 ofFIG. 4;

FIG. 6 is a fragmentray interior elevational view of the pulser of FIGS.1 to 5, looking in the direction of the arrows 6-6 in FIG. 4;

FIG. 7 is a schematic diagram of the electrical connections of thepulser of FIGS. 1 to 6; and

FIG. 8 is a vertical sectional view of a modified type of energy storagemodule and its cover member.

Referring more particularly to the drawing, the pulser of FIGS. 1 to 6includes an elongated upright hollow support 10 of insulating materialwhich is mounted at its lower end on a base 12 having an upper platemember 14 of metal such as brass. As shown most clearly in FIG. 4, thelower end of the support 16 is closed by a metal plate 16 suitablysecured thereto, for example by mounting a plurality of screws 18 aroundthe periphery of the plate and casting the support 10 around the screws18 and the plate 16. The upper end-of the support is closed by aremovable cover plate 20 of insulating material with a gasket 22positioned between the cover plate and the support 10. The cover plateis held in position by a plurality of screws 24. An output connector andspark gap member assembly 26 is carried by and extends through the coverplate 20. The details of such assembly will be described more in detailbelow.

A plurality of energy storage modules 28 are detachably connected to theouter surface of the support 10 and arranged in two vertical rows, oneon each side of the support. Each module has a cup-shaped cover member30 separately detachably connected to support 10. The support 10 alsocarries in its interior a plurality of metal spark gap members 32 and34, each surrounded for the major portion of its length by a sleeve 36of insulating material. The support 10 also carries adjacent its lowerend a modified type of spark gap member 38 to which is supplied atriggering pulse to trigger the breaking down of its associated sparkgap and thus the various other spark gaps provided by the spark gapmembers 32 and 34. All of the spark gap members are arranged in twovertical rows, one at each side of the support 10, to provide aplurality of spark gaps positioned in a common light path. It will benoted that the modules of the two rows of modules 28 and their covers 30are ofi'set vertically of the support 10 so that the spark gap members34 associated with the lower portions of each module 28 are each inhorizontal alignment with the upper spark gap member 32 of the nextlower module 28 to form the spark gaps and that the lowermost upperspark gap member 32 is in horizontal alignment with triggering spark gapmember 38 to form the triggered spark gap.

The upper and lower spark gap members 32 and 34 respectively associatedwith each module 28 form part of a subassembly including a supportelement 40 of insulating material having a cylindrical outer surfacewith a reduced portion 42. The support 10 has an inner shell 44 and thereduced portion 42 of the support element may be initially positioned ina suitably located aperture in such shell and the remainder of thesupport 10 cast around such support element 40. Each support element 40has an internally threaded socket 46 in its outer surface and eachcup-shaped module cover member has a reduced rim portion which isexternally threaded and received in the socket 46. An 0 ring 48surrounds such reduced portion of the rim of the cover 30 to provide agasket between such cover and the support element 40.

Each support element has an hourglass shaped opening 50 extendingaxially therethrough as shown most clearly in FIG. 6, providingthickened rim portions each of which has a bore 52 extendingtherethrough in a direction axially of the support element. A metal nut54 shown in FIG. 4 is positioned in such bore and receives thescrew-threaded end of a spark gap member 32 or 34 so that each suchspark gap member can be adjusted longitudinally of itself to vary thelength of the spark gap between its inner end and the end of anotherspark gap member carried by the opposite side of the support 10. Eachspark gap member 32 or 34 has a socket 56 in its outer end for receptionof a plug 58 forming part of a module 28 as described below and theouter end of such socket can be formed to receive a suitable key orwrench to enable adjustment of the spark gap members from the exteriorof the support 10 when the corresponding modules 28 are removed.

The spark gap member 38 has an inner metal member 60 surrounded by asleeve of insulating material in turn surrounded by a metal sleeve 62. Anut 64 secured in a bore 65 in a modified support element 66 receives anenlarged threaded end of the inner member 60 which also has a socket 56for reception of a plug. The bore 65 also has secured therein anothernut 67 which is separated from the nut 64 by a washer of insulatingmaterial and receives a threaded inner end of the metal sleeve 62. Otherthan having a larger bore to receive the nuts 64 and 67, the supportelement 66 is similar to the support elements 40.

The modules 28 each include an upper elongated sup port member 68 ofinsulating material and a lower elongated support member 7 6 parallel toand spaced vertically from the upper support member. Such supportmembers each carry one of the plugs 58 at its inner end. A pair of rigidcapacitor elements 72 extend between and are rigidly secured to theupper support member 68 and lower support member to form aself-supporting module. The capacitor elements are secured to the lowersupport member 70 by thumb screws 73 which can be loosened to enablealignment of the plugs 58 with their sockets and then tightened afterinstallation of the module to insure good electrical connections.

A pair of inductors 74 and 76 are wound on the upper support member 68.The inductor is electrically connected between the upper ends of the twocapacitor elements 72 and the inductor 76 is connected between the upperend of the inner one of such capacitors and the connecting plug 58secured to the inner end of the support member 68. The similar plug 58secured to the inner end of the metal support member 70 is connected tothe lower ends of the capacitor elements 72 by such lower supportmember. It will be apparent that the capacitor elements 72 and inductors74 and 76 form a two section open ended artificial transmission line. Itwill also be apparent that the cover member 30 for each module can beremoved by unscrewing it from its socket and that upon removal of itscover, each module 28 can be removed for repair or replacement by merelypulling each module away from the support It). The same or differentmodule and cover member can then be replaced in reverse order. It willbe noted that one of the capacitors opening 50 As shown most clearly inFIGS. 3 and 5, the support 10 contains a pair of elongated upstandingcylindrical members imbedded in the insulating material forming the bodyof the support. One of such cylindrical members has a series circuit ofinductors 82 wound thereon and the other of such cylindrical members hasa series circuit of similar inductors 83 wound thereon. As shown in FIG.5, connector members 84 having their ends irnbedded in the cylindricalmembers are connected to the ends of such inductors and to the nuts 54making electrical contact with the spark gap members 32 and 24. Theinductors 82 on one of said cylindrical members 80 are thus connected tospark gap member 32 and the inductors 33 on the other cylindrical member80 are connected to the spark gap members 34, with the next to the lowerinductor 83 connected between a spark gap member 34 and the inner member60 of the spark gap member 38 and the lowermost inductor 83 connectedbetween such inner member 60 and ground.

The lower end of the support 10 has two cable connector sockets 86 and88 of insulating material imbedded therein and provided with metalliccentral connecting elements 90 and 92, respectively. The connectorelement 90 of one of such sockets 86 is connected to the nut 67 incontact with the outer metal sleeve 62 of the spark gap member 38 by aconnector (not shown) but similar to the connectors 84 of FIG. toprovide an input for a triggering voltage from a trigger transformer 93energized from a suitable trigger amplifier (not shown). The connectorelement 92 of the other of such sockets 88 is connected by a similarconductor to the lower end of the lowermost inductor 82 to provide aninput from a high voltage transmission line charging current source. Atube 94 extending through the wall of the support is positioned adjacentthe connector socket-s 86 and 88 to provide for introducing gas underpressure into the interior of the support 10.

The output connector and spark gap member assembly 26 provides an outputconnection to an output cable. It

includes a threaded metal member 95 extending vertically through theupper cover plate 20 and held rigidly in position by a pair ofnuts 96threaded on the member 95 and tightened into sockets on opposite facesof the'cover plate 20. A ball 97 providing an output spark gap member ispinned to the lower end of the threaded member 95 in spaced relation tothe uppermost spark gap member 32 to provide an output spark gap. Acable connector is swiveled to the upper end of the threaded member 95and includes an inner metal connector member 98 having a conductorreceiving socket 100 in its end and an outer insulating sheath 102covering and extending forwardly of the connector member 98 to provide acable receiving socket 104. The metal connector member is held inposition by a screw 106 threaded into the upper end of the member 95 andhaving a washer below its head in engage ment with a compression spring108 positioned in a socket in the metal connector member 98 so as toresiliently press such connector member against the upper end of themember 95.

The pulser above described can be fabricated in a series of stepsincluding forming the inner shell 44 of the support 10 with suitableapertures therein to receive the support element 40 and then installingsuch support members in such apertures and positioning such shell uponthe lower closure plate 16. The support members may be previously formedby machining from a body of insulating material and adhesively securingthe nuts 54 and sleeves in position or can be formed by a resin castingoperation in which case the nuts 54 and sleeves 36 may be held inposition in a suitable mold and the body of the support member castaround such nuts and sleeve. The support element 66 and its containednuts, 54, 64 and 67 can be similarly fabricated.

The vertically extending cylindrical members 80 of insulating materialcan be wound with the inductors 82 and 83 with the connectors 84extending therefrom and then placed in position with respect to theshell 44 and the base plate 16. The connectors 84 can be inserted intosuitable bores in the support elements so as to make contact with thenuts 54 and 64. The cable connector sockets 86 at the lower end of thesupport 10 with suitable connections extending to the connector members90 can also be positioned on the inner shell and the tube 94 may bepositioned to extend through an aperture in the inner shell. Theresulting assembly can then be placed in a suitable mold and the bodyportion of the support 10 cast around the inner shell 44 and the supportelements and 66, as well as around the cable connector sockets 86, thetube 94 and the base plate 16. The resulting support 10 can then besecured to its base 12 and can have installed thereon the other portionsof the complete pulser including the spark gap members 32 and 38, themodules 28 and covers 30 therefor, and the upper cover plate 20 andparts carried thereby.

A schematic wiring diagram of the pulser is shown in FIG. 7 and it willbe noted that the inductors 82 and 83 and their connections form acircuit for charging in parallel the various transmission linesincluding the inductors 76 and capacitor elements 72 from a source ofDO. potential (not shown) having its high voltage terminal connected tothe connector 92 and its other terminal connected to ground. A highvoltage triggering pulse, for example, a 10 kv. pulse, may be impressedupon the outer sleeve 62 of the triggering'spark gap member to breakdown one of the spark gaps and emit ionizing radiation from such one gapto all of the remaining gaps to cause all of the spark gaps to breakdown substantially instantaneously and discharge the chargedtransmission lines in series. The transmission lines may for example becharged to a voltage as high as 30 kv. each and twenty-four suchtransmission lines in series will produce an output voltage equal toapproximately 300 kv. As an example, a suitable length for the variousspark gaps is %-inch. For charging voltages above approximately 18 kv.nitrogen under pressure is preferably introduced through the tube 94,such nitrogen pressure ranging from 0 p.s.i. gauge at 18 kv. to 13p.s.i. at 30 kv. By employing ceramic capacitors for the capacitorelements 72 sufficient energy storage to produce currents up to 2000amperes discharged through 150 ohms and a pulse width of 0.2 microsecondhas been obtained in a relatively small sized device. For example, adevice capable of such operation may be approximately 8 inches wide, 15inches long and 57 inches high. The pulses produced can be employed inan X-ray tube or other load connected directly between the outputconnector member 98 and ground or can be transmitted for substantialdistances by means of a coaxial cable or a twinax cable, for example a300 ohm line.

Various sized modules may the easily substituted for each other. Thewidth of the pulse produced measured in microsecond will beapproximately twice the time for a voltage wave to travel the etfectivelength of the transmission lines. For very narrow pulses, modifiedmodules such as the module 109 of FIG. 8 containing a coiled coaxialcable 110 can be employed. Each cable 110 is open at one end and has itsother end connected between plugs 58 secured in an end plate 112 for themodule. The coiled cable 110 is contained in a cupshaped casing 114secured to and having its open end closed by the end plate 112. Themodules 109 may each have a cover 116 which may be similar to the covers30 except for being longer to provide more internal space.

While the present application discloses the preferred embodiments of theinvention, it is to be understood that variations can be made in thedetails thereof.

We claim:

1. A high voltage pulser comprising:

an elongated hollow support forming a gas tight container,

a plurality of pairs of spark gap members spaced longitudinally of saidsupport and each including a first spark gap member and a second sparkgap member having portions spaced from each other to provide a spark gapwithin said container,

a plurality of similar energy storage modules each including an openended transmission line of substantially the same characteristicimpedance,

means for mounting each of said modules on said support and connectingone end of said transmission line of each module between a first memberof one of said pairs of members and a second member of another of saidpairs of members, and for positioning the spark gaps formed between saidmembers in a common light path,

inductor means connecting said first members together and inductor meansconnecting said second members together to provide a circuit forcharging said transmission lines from a high voltage D.C. source butisolating said first members from each other and also isolating saidsecond members from each other with respect to rapidly changingcurrents,

means to introduce gas into said spark gaps and initiate the break downof one of said spark gaps so that ionizing radiation is emitted fromsaid one gap to cause all of said spark gaps to break down substantiallysimultaneously and connect said one ends of said transmission lines in aseries circuit,

and pulse output means connected in series with said series circuit.

2. A high voltage pulser comprising:

an elongated hollow support structure closed at its ends to provide aclosed gas tight chamber,

a plurality of pairs of spark gap members mounted within and spacedlongitudinally of said support and each including a first spark gapmember and a second spark gap member projecting toward each other fromopposite sides of said chamber and spaced from each other to provide asparkgap,

a plurality of similar energy storage modules containing lumped constanttransmission lines of substantially the same characteristic impedance,

means for mounting said modules on the exterior of said supportstructure and for connecting each of said modules between a first memberof one of said pairs of members and a second member of another of saidpairs of members, and for positioning the spark gaps formed between saidmembers in a common light path within said chamber,

circuit means for charging said transmission lines from a high voltageD.C. source,

cover means for sealing said chamber,

means for introducing gas under pressure into said chamber,

means to initiate the breakdown of one of said spark gaps to emitionizing radiation from said one gap to the remaining gaps in order tocause all of said spark gaps to break down at substantially the sametime and connect said transmission lines in a series circuit,

and pulse output means connected in series with said series circuit.

3. A high voltage pulser comprising:

an elongated hollow support of insulating material closed at its ends toprovide a closed chamber,

a plurality of pairs of elongated spark gap members mounted within andeach including a first spark gap member and a second spark gap memberprojecting from each other from opposite sides of said chamber andhaving inner ends spaced from each other to provide a spark gap, saidmembers being positioned in two longitudinally extending rows with saidfirst members alternating with said second members in said rows and eachbeing mounted in said support for adjustment longitudinally of itself tovary the length of one of said spark gaps,

a plurality of similar energy storage modules each including an openended transmission line having series inductors and shunt capacitors,said modules each. including spaced elongated support elements,

rigid capacitor elements extending between and rigidly secured to saidsupport elements and inductors wound on one of said support elements andconnecting ends of said capacitor elements,

plug in means carried by the ends of said support elements for mountingsaid modules on the exterior of said support with said modules arrangedin longitudinal rows on opposite sides of said support and forconnectingone end of said transmission line of each of said modules between afirst member of one of said pairs and a second member of another of saidpairs,

inductor means including a series circuit of inductors extendinglongitudinally of said support on opposite sides thereof and betweensaid rows of modules, the inductors of one of said series circuits beingconnected between pairs of said first members and the inductors of theother of said circuits of inductors being connected between pairs ofsaid second members to provide a circuit for charging saidtransmission-lines from a high voltage D.C. source but isolating saidfirst members from each other and also isolating said second membersfrom each other with respect to rapidly changing currents,

removable cover means for said modules cooperating with said support toclose said chamber and provide for maintaining a gas pressure aboveambient atmospheric pressure in said chamber,

an auxiliary spark gap member at one end of said support cooperatingwith one of said first spark gap members to provide an output spark gap,

means including an auxiliary conductor forming part of but insulatedfrom one of said members to initiate the breakdown of one of said spar-kgaps to cause all of said spark gaps to break down and connected to saidone ends of said transmission lines in series,

and pulse output means connected in series with said auxiliary memberand the end of the last mentioned series circuit which is remote fromsaid auxiliary member.

4. A high voltage pulser comprising:

an elongated'support forming a gas filled container,

a plurality of pairs of elongated spark gap members mounted on saidsupport and each including a first spark gap member and a second sparkgap member having ends spaced from each other to provide a spark gap,said members being positioned to form a plurality of spark gaps inalignment in a common light path within said container,

a plurality of similar energy storage modules each including an openended transmission line of substantially the same characteristicimpedance and having spaced elongated support elements,

rigid capacitor elements extending between and rigidly secured to saidsupport elements and inductors wound on one of said support elements andconneoting ends of said capacitor elements,

plug in means carried by the ends of said support elements for mountingsaid modules on said support "and connecting, one end of saidtransmission 'line of each of said modules between a first member of oneof said pairs and a second member of another of said pairs,

circuit means for charging said transmission lines from a high voltageD.C. source,

means to initiate the breakdown of one of said spark gaps to emitionizing radiation from said one gap to the other gaps which causes allof said spark gaps to break down substantially simultaneously andconnect said one ends of said transmission lines in a series circuit,

and pulse output means connected in series with said transmission lines.

5. A high volt-age pulser comprising:

an elongated support torming a gas tight container,

.a plurality of pairs of elongated spark gap members mounted on saidsupport and each including a first spark gap member and a second sparkgap member having inner ends spaced from each other to provide a sparkgap, said members being positioned to form a plurality of spark gap-s ina common light path within said container,

a plurality of similar energy storage modules, each including acontainer and a coiled coaxial cable in said container providing an openended transmission line,

plug in means carried by said modules for mounting said modules on saidsupport and connecting one end of said transmission line of each of saidmodules between a first member of one of said pairs and a second memberof another of said pairs,

circuit means for charging said transmission lines from a high voltageD.C. source,

means to initiate the breakdown of one of said spark gaps to emitionizing radiation from said one gap to the remaining gaps which causesall of said spark gaps to break down substantially simultaneously andconnect said one ends of said transmission lines in a series circuit,

and pulse output means connected in series with said transmission lines.

6. A high voltage pulser comprising:

a gas filled container;

a plurality of electrical signal transmission lines of substantially thesame uniform characteristic impedance to prevent signal reflections andto enable the production of a rectangular output pulse when saidtransmission lines are connected together;

a plurality of spark gap electrodes connected to said transmission linesto forma plurality of spark gaps between the transmission lines whichconnect said transmission lines together when said spark gaps breakdown;

means for charging each of said transmission lines to a predeterminedvoltage and for enabling the transmission lines to store the chargeuntil the spark gaps break down and discharge said transmission lines;

means for supporting said electrodes within said container in order toposition said spark gaps in a common light path; and

means for causing ionizing radiation to be transmitted along said paththrough the spark gaps to cause said spark gaps to break down atsubstantially the same time.

7. A high voltage pulser comprising:

a gas tight container;

a plurality of electrical signal transmission lines of su stantially thesame uniform characteristic impedance to prevent. signal reflections andto enable the production of a rectangular output pulse when saidtransmission lines are connected together;

a. plurality of spark gap electrodes connected to said transmissionlines to torm a plurality of spark gaps between the transmission lineswhich connect said transmission lines in series when said spark gapsbreak down;

means for charging said transmission lines in parallel to apredetermined voltage and for enabling the transmission lines to storethe electrical energy until the spark gaps break down and discharge saidtransmission lines;

means for supporting said electrodes within said container in order toposition said spark gaps in alignment in a common light path so thateach gap sees all the remaining gaps; and

means for causing radiation to be transmitted along said path to causesaid spark gaps to break down substantially simultaneously.

References Cited by the Examiner UNITED STATES PATENTS 1,974,328 9/1934Bouwers 30 7-110 X 2,254,836 9/1941 Boldingn 307-108 2,470,118 5/1949Trevor 307-110 X 2,534,758 12/1950 Titterton 307-110 X 2,578,263 12/1951Perkins 320-1 2,695,374 11/1954 Jeppson 321-15 X 2,898,523 4/ 1959Charles 317-99 3,059,165 10/1962 Meykar 321-15 FOREIGN PATENTS 389,8133/ 1933 Great Britain.

407,837 3/1934 Great Britain.

837,958 6/1960 Great Britain.

IRVING L. SRAGOW, Primary Examiner.

MILTON C. HIRSHFIELD, Examiner.

1. A HIGH VOLTAGE PULSER COMPRISING: AN ELONGATED HOLLOW SUPPORT FORMINGA GAS TIGHT CONTAINER, A PLURALITY OF PAIRS OF SPARK GAP MEMBERS SPACEDLONGITUDINALLY OF SAID SUPPORT AND EACH INCLUDING A FIRST SPARK GAPMEMBER AND A SECOND SPARK GAP MEMBER HAVING PORTIONS SPACED FROM EACHOTHER TO PROVIDE A SPARK GAP WITHIN SAID CONTAINER, A PLURALITY OFSIMILAR ENERGY STORAGE MODULES EACH INCLUDING AN OPEN ENDED TRANSMISSIONLINE OF SUBSTANTIALLY THE SAME CHARACTERISTIC IMPEDANCE, MEANS FORMOUNTING EACH OF SAID MODULES ON SAID SUPPORT AND CONNECTING ONE END OFSAID TRANSMISSION LINE OF EACH MODULE BETWEEN A FIRST MEMBER OF ONE OFSAID PAIRS OF MEMBERS AND A SECOND MEMBER OF ANOTHER OF SAID PAIRS OFMEMBERS, AND FOR POSITIONING THE SPARK GAPS FORMED BETWEEN SAID MEMBERSIN A COMMON LIGHT PATH, INDUCTOR MEANS CONNECTING SAID FIRST MEMBERSTOGETHER AND INDUCTOR MEANS CONNECTING SAID SECOND MEM-